SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7d947eb4a8a0fcbc4418e89b394e87ae94a8c3f644a8a500dcd74cca94434cd3' 
  AND token = 'bXHLEEpo0M6Bq+/cs3kMlY5bfDxFtAFekibayrfOx34=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}